syzbot

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BUG: KCSAN: data-race in __io_fill_cqe_req / io_uring_poll

read-write to 0xffff888138227a50 of 4 bytes by task 30577 on cpu 0:
 io_get_cqe fs/io_uring.c:2241 [inline]
 __io_fill_cqe_req+0x242/0x5a0 fs/io_uring.c:2476
 __io_req_complete_post fs/io_uring.c:2580 [inline]
 io_poll_task_func+0x1a8/0x280 fs/io_uring.c:6940
 handle_tw_list fs/io_uring.c:2938 [inline]
 tctx_task_work+0x8d0/0xc10 fs/io_uring.c:2967
 task_work_run+0x8e/0x110 kernel/task_work.c:177
 io_run_task_work fs/io_uring.c:3218 [inline]
 io_uring_try_cancel_requests+0x2d2/0x30b fs/io_uring.c:11516
 io_uring_cancel_generic+0x24b/0x415 fs/io_uring.c:11666
 __io_uring_cancel+0x11/0x20 fs/io_uring.c:11703
 io_uring_files_cancel include/linux/io_uring.h:44 [inline]
 do_exit+0x2c6/0x1720 kernel/exit.c:750
 do_group_exit+0xa5/0x160 kernel/exit.c:925
 get_signal+0xf54/0x1020 kernel/signal.c:2857
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888138227a50 of 4 bytes by task 30585 on cpu 1:
 __io_cqring_events fs/io_uring.c:2197 [inline]
 io_cqring_events fs/io_uring.c:3201 [inline]
 io_uring_poll+0xc5/0x150 fs/io_uring.c:11232
 vfs_poll include/linux/poll.h:88 [inline]
 io_poll_check_events+0x1ee/0x4f0 fs/io_uring.c:6878
 io_poll_task_func+0x31/0x280 fs/io_uring.c:6926
 handle_tw_list fs/io_uring.c:2938 [inline]
 tctx_task_work+0x8d0/0xc10 fs/io_uring.c:2967
 task_work_run+0x8e/0x110 kernel/task_work.c:177
 get_signal+0xeca/0x1020 kernel/signal.c:2634
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00001c51 -> 0x00001c52

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30585 Comm: syz-executor.4 Not tainted 5.19.0-syzkaller-01583-g7d0d3fa7339e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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